The Messenger of Allah ﷺ sent word to the tribe of Banu Lihyan saying that one man out of every two should go out on the expedition. Then he said to the one who stayed behind, "Whichever of you looks after the family and property of the one who goes out, treating them well, will receive a reward equal to half the reward of the one who went out."
أن رسول الله ﷺ بعث إلى بني لحيان: ليخرج من كل رجلين رجل، ثم قال للقاعد: أيكم خلف الخارج في أهله وماله بخير، كان له مثل نصف أجر الخارج.
Muslim narrated it in "The Book of Leadership" (1896:138), from Saeed bin Mansur, who said, Abdullah bin Wahb told us, Amr bin Harith informed me, from Yazid bin Abu Habib, from Yazid bin Abu Saeed, the freed slave of Mahri, from his father, from Abu Saeed Khudri, and he related it.